Investigation of sorption mechanism of methylene blue, congo red and tannic acid from aqueous solutions onto magnetic composite sorbent obtained from alkaline pretreated spent coffee grounds

In this article, a novel magnetic composite material obtained from alkaline pretreated spent coffee grounds was used for investigating of the sorption mechanism methylene blue, congo red and tannic acid aqueous solutions. order to clarify mechanisms were analyzed adsorption kinetics models (external internal diffusion; chemical (pseudo-first order, pseudo-second order); intraparticle diffusion) thermodynamics. The results showed that all studied sorbates controlled by mixed diffusion model rate revealed three stage mass transfer. process onto Fe 3 O 4 /PVA/APSCGs sorbent spontaneous endothermic. Based on results, it concluded removal may be assumed both physisorption chemisorption.